Low-profile luminaire having a reflector for mixing light from a multi-color linear array of LEDs

Abstract

A linear array of LED light sources in a plurality of colors is situated along the length of a reflector which is positioned so that it receives substantially all the light within the semi-cone angles of the sources, and is shaped so that it is illuminated substantially uniformly along its width. The reflector may be configured as a smooth Lambertian surface, or may be configured as a curve approximated by a series of flat specular reflecting segments.

What is claimed is:  
     
       1. A luminaire comprising 
       a linear array of light injectors comprising at east one injector for emitting light in each of a plurality of colors, each injector emitting rays of light in a cone having a semi-angle θ s , said array being parallel to the y-axis of an x-y-z coordinate system, and arranged so that substantially all of said light is emitted in the positive x and z directions, and  
       a reflector having a surface with a shape defined by a curve in the x-z plane in the positive x and z directions, said surface being formed by a projection of said curve parallel to the y-axis, said surface being arranged to receive substantially all of said light within the semi-angles θ s  of the injectors in the array.  
     
     
       2. A luminaire as in claim  1  wherein said reflector is a Lambertian reflector. 
     
     
       3. A luminaire as in claim  2  wherein said surface of said reflector is coated with a phosphor. 
     
     
       4. A reflector as in claim  3  wherein said surface is brushed aluminum. 
     
     
       5. A luminaire as in claim  1  further comprising a pair of planar reflecting sidewalls parallel to the x-z plane and bounding the surface of the reflector. 
     
     
       6. A luminaire as in claim  5  wherein said sidewalls are specular reflecting. 
     
     
       7. A luminaire as in claim  1  wherein the reflector is shaped so that the injectors illuminate it uniformly in the x-direction. 
     
     
       8. A luminaire as in claim  1  wherein said rays of light include a pair of extreme rays which bound the light emitted from said array in the x-z plane, one of said extreme rays being parallel to the x-axis at z=0, the other of said extreme rays being emitted at z=z o  at an angle of 2θ s ) to the x-axis. 
     
     
       9. A luminaire as in claim  8  wherein the said curve is bounded by a first terminal point at (x,z)=(W,0), and a second terminal point at (x,z)=z o +αW tan (2θ s ), wherein α is a design parameter. 
     
     
       10. A luminaire as in claim  1  wherein each injector comprises an LED emitting light in the respective color, and design optics for confining the emitted light within the cone having semi-angle θ s . 
     
     
       11. A luminaire as in claim  1  wherein said linear array comprises at least two rows of light injectors. 
     
     
       12. A luminaire as in claim  1  wherein at least some of said injectors emit light in elliptical cones. 
     
     
       13. A luminaire as in claim  12  wherein said elliptical cones are wider in the x-y plane than in the x-z plane. 
     
     
       14. A luminaire as in claim  1  wherein at least some of said cones have axes which form an acute angle with the x-z plane. 
     
     
       15. A luminaire as in claim  14  wherein said array has a midpoint, injectors which are remote from said midpoint having axes which are rotated toward said midpoint. 
     
     
       16. A luminaire as in claim  1  wherein said curve is approximated by a series of flat segments arranged parallel to the y-axis, and at an orientation which varies with the x-coordinate for each slat. 
     
     
       17. A luminaire as in claim  16  wherein each segment is a specular reflector. 
     
     
       18. A luminaire as in claim  17  wherein said slats are positioned and arranged to reflect light substantially parallel to the z-axis.